Refactor global configuration page and navigation; add media library page; enhance streamer configuration with detailed options

- Removed the global configuration form and redirected to the consolidated settings page.
- Updated the dashboard to provide feedback when no streamers are configured and added edit links for each streamer.
- Introduced a new media library page to display media files from the configured archive root.
- Enhanced the streamer configuration page with additional options for overrides and settings, including a confirmation modal for deletion.
- Updated the layout and styles for improved user experience and navigation.
- Switched from file-based password storage to database-backed user credentials management in AuthService.
- Applied EF migrations on application startup to ensure database schema is up-to-date.

dotnet/src/TwitchArchive.Core/Persistence/ArchiveDbContext.cs

@@ -10,5 +10,6 @@ namespace TwitchArchive.Core.Persistence
         public DbSet<StreamSession> StreamSessions { get; set; } = null!;
         public DbSet<ArchiveJob> ArchiveJobs { get; set; } = null!;
         public DbSet<StreamerState> StreamerStates { get; set; } = null!;
+        public DbSet<TwitchArchive.Core.Persistence.Models.UserCredential> UserCredentials { get; set; } = null!;
     }
 }

dotnet/src/TwitchArchive.Core/Persistence/ArchiveDbInitializer.cs

@@ -0,0 +1,30 @@
+using System;
+using Microsoft.EntityFrameworkCore;
+
+namespace TwitchArchive.Core.Persistence
+{
+    public static class ArchiveDbInitializer
+    {
+        public static void EnsureUserCredentialsTable(IDbContextFactory<ArchiveDbContext> factory)
+        {
+            if (factory == null) throw new ArgumentNullException(nameof(factory));
+            try
+            {
+                using var ctx = factory.CreateDbContext();
+                var conn = ctx.Database.GetDbConnection();
+                try { conn.Open(); } catch { /* ignore open errors */ }
+                using var cmd = conn.CreateCommand();
+                // Create table if it doesn't exist (SQLite syntax)
+                cmd.CommandText = @"CREATE TABLE IF NOT EXISTS UserCredentials (
+                                        Id INTEGER PRIMARY KEY AUTOINCREMENT,
+                                        PasswordHash TEXT NOT NULL
+                                    );";
+                cmd.ExecuteNonQuery();
+            }
+            catch
+            {
+                // Initialization should not crash the app; log if needed
+            }
+        }
+    }
+}

dotnet/src/TwitchArchive.Core/Persistence/Models/UserCredential.cs

@@ -0,0 +1,8 @@
+namespace TwitchArchive.Core.Persistence.Models
+{
+    public class UserCredential
+    {
+        public int Id { get; set; }
+        public string PasswordHash { get; set; } = string.Empty;
+    }
+}